This invention relates to welding methods, and more particularly to laser welding methods.
High power lasers have been used since the early 1970's to weld thick structural materials including the HY-steels. Investigators have reported both the excellent properties and the advantages of laser welding. No experimenters, however, are known to have successfully fabricated laser weldments which meet the Navy's impact fracture toughness criteria, particularly at low temperatures. In order for high strength steels to be used in submarines and deep submersible vessels which reach great depths and travel in the Arctic Ocean, these criteria must be met.
Heretofore, heat treatment and application of filler wires of similar composition to the base plate have been used to improve the toughness of laser beam weldments.